In particular, the present invention applies to a wheel hub unit of the type comprising an inner ring and an outer ring rotatable with respect to each other due to the interposition of one or more crowns of rolling bodies, and either the inner ring or the outer ring of which may be provided with a respective flange for the connection to a wheel or to an upright according to the type of application.
Noisiness and vibrations may occur in use in the above-mentioned wheel hub units due to wear or defects of one of the components. If such noisiness and vibrations occur prematurely, e.g. when the vehicle to which they are mounted is still under guarantee, upon the replacement of the wheel hub unit the vehicle's manufacturer sends the replaced unit to the manufacturer as defective unit. The manufacturer of the wheel hub unit must therefore check whether the defects reported are actually present, and such a check currently involves not only rather considerable times and costs but, in some wheel hub units, it may be necessary to destroy the unit itself and simply disassemble it.
Moreover, the experience in the field has proved that not all the wheel hub units returned by the vehicle's manufacturer as being defective are actually such. This may happen either because the service center carries out a wrong replacement since the noise and vibrations detected by the user do not come from the unit but from another source, such as for example the tire, or because since it is not possible to positively determine which of the two units of the same axle must be replaced, the service center replaces both of them.
It is apparent that the situation described involves costs for the manufacturer of rolling bearings, which costs could be avoided if it were possible to determine the actually defective bearings without the need for disassembly operations which, in some cases, are also destructive for some components. Moreover, if the vehicle's manufacturer were able to immediately detect the rolling bearings that emit abnormal noisiness and vibrations among those replaced by the service centers, he would avoid the costs and burdens related to the return of bearings/units deemed defective to the supplier of such bearings/wheel hub units.